Actuator for hoist pit closures



Dec. 4, 1951 Filed Dec. 7, 1948 .T. O. SNIDER ACTUATOR FOR HOIST PIT CLOSURES 4 Sheets-Sheet 1 IN V EN TOR.

77/5apor5 0. 54/051 Dec. 4, 1951 r. o. SNIDER ACTUATOR FOR HOIST PIT CLOSURES 4 She ets-Sheet 2 Filed Dec. 7, 1948 INVENTOR.

Dec. 4, 1951 1Q. SNIDER 2,577,377

ACTUATOR FOR HOIST PIT CLQSURES Filed Dec. 7, 1948 4 Sheets-Sheet 3 INVENTOR.

Dec. 4, 1951 T. o. SNIDER ACTUATOR FOR HOIST PIT CLOSUREIS 4 Sheets-Sheet 4 Filed Dec. 7, 1948 JNVENTOR. 77/5020 dams/g Patented Dec. 4, l951 1 2,577,377 ACTUATOR son nors'r PIT CLOSURES Theodore 0. Snider, Cleveland, Ohio, assignor, by mesne assignments, to Harold C. Schott,

Cleveland, Ohio Application December '7, 1948, Serial No. 64,015

This invention relates to automobile lifts in general, but relates more particularly to a lift which is retractable into a covered pit below floor level, and is related specifically to automatically controlled covers for a lift pit adapted to open and allow the superstructure of alift to pass thereby and immediately close thereafter to cover the pit and provide useful floor area." I

Prior automobile lifts generally consisted of a single hydraulic post' and an H-shaped superstructure. The post operates in a cylinder extending into the floor of the service station or garage and the superstructure rests upon the floor. A vehicle to be lifted is driven upon the superstructure and then both the superstructure and the vehicle are lifted off of the floor by the hydraulic post.

Twopost lifts have been developed in which one post is adapted to contact the front axle of a vehicle, and a second post isadapted to contact the rear axle of a vehicle. Many advantages in automotive servicing and repair work are obtainable by two-post lifts. The automatically operated covers for a, pit of this invention, into which the entire lift including the superstructure can withdraw and be covered, has made the twopost lift much more valuable. The large amount of floor space normally occupied by an automobile lift is available in the modern garage for other purposes when the lift is not being used. The space thus saved is equivalent to 'anentire supplemental garage in service stations and service garages having numerous lifts.

Therefore, an object of this invention is to provide an improved vehicle lift. I

Another object of this invention is to provide a pit below floor level for a vehicle lift, and provide doors to cover the pit at all times except when the superstructure of the lift is passing in or out of the pit.

Another object of this invention is to provide automatically operable and closable doors for a lift pit.

Another object of this invention is to provide a lift pit having longitudinal and lateral doors covering the H-shaped superstructure of one post of a two-post lift; adapting the lateral doors to operate the longitudinal doors by lever linkage therebetween; and adapting the lift to operate the lateral doors.

A still further object of this invention is to adapt the lever linkage between the doors to transmit forcein only one direction in order that the superstructure may push its way through the doors on its Way up out of the pit, and'th'e lateral 3 Claims. (Cl. 254-89) 2 doors open the longitudinal doors when the lift descends.

Other objects and a fulle .understanding of this invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawing, in which:

Figure l is a perspective view of a two-post lift which is retractable within a covered floor pit, the rear post being provided with the automatically operable doors of this invention;

Figure 2 is a partial cross-sectional view taken from the position indicated by the line 2-2 of Figure 1, but with the lift entirely retracted into the pit and the doors being clos d thereov r;

Figure 3 is a view similar to Figure 2, with the lift extended out of the lift pit;

Figure 4. is a view similar to Figures 2 and 3, with the lift at a position just prior to entering into the lift pit; and

Figure 5 is a cross-sectional View through the pit substantially along line 55 of both Figures 1 and 2.

In the Figure 1 of the drawing the general plan of a two-post lift is illustrated having a front lift ll of conventional construction adapted to withdraw into a pit l8, and a rear lift [9 adapted to withdraw into a lift pit-I3. The principles of this invention, and an actual embodiment of the invention, are illustrated only in connection with the rear lift i9, because substantially all lifts provided for service stations and garages require only that the rear lift H! has a long superstructure to compensate for the differences between the wheel bases of various makes and models of vehicles. The front lift I1 is therefore quite small and may be covered by any suitable type of door. The pit I8 is relatively small, and therefore great concern is not required as to whether the pit I8 is closed after the lift l1 extends therethrough. It is to be understood, of course, that the principles of this invention may very readily be applied to the front lift ll, but for the purpose of setting forth the invention herein, the front lift I! and the pit 18 are not illustrated with the automatic doors of the present invention, but the invention is illustrated in the rear lift is and the pit l 3.

The rear lift I9 comprises a hydraulic post ID of suitable standard design and construction, having a cross member i i bolted or otherwise suitably fastened on the end of the post. The Figures 1 and 2 best illustrate the position of .two spaced, longitudinally extended, upright memrs l2 securely mounted on each end of the cross gage the axle of a vehicle parked over the lift pit;

I3. In other words, the vehicleis/driven. over the lift with the front axle thereof positioned over the front lift H, and the rear axle;is;.posia tioned over the superstructure..ofitherrear lift. 3

IS. The axle-engaging blocks [-4 are thereafter shifted, either by hand shiftingonby improved remote control shifting, to a position belowthe rear axle of the vehicle. Thereafter, astha two. posts of the lift are raised the axles of the vehicle. willbev accurately engaged andthe vehicle will be lifted free of interfering lift structure.

Aspreviously stated, the rear lift 19 .is finerally provided with a-longitudina 'y extendin superstructure in order that the two-:postlift may accommodate vehiclewheel bases within a wide range of variation. Accordingly, ii -order to. retract. the large superstructure within a floor pit when the lift. isznot in. service, relatively large .fioor openings varerequired. These largefloor openings,.if left uncovered, constitute a physical hazard for: the service attendant, as-well as a nuisance because of the fact thata droppedtool .Will invariably roll into an, open pit..

In the Figure 1. of the drawings, a 'perspective view of the improved pit covering means of this invention is illustrated, and in the remaining views the details of construction and operation are. set forth. The lift it is illustrated with (an H-shaped superstructure, and the pit-ttis suitably formed with an H-shape to conform'to. the shapeof the superstructure. :Therpitviii includes a horizontal or cross pit 2B, and two spaced longitudinally extending side pits 2| andZZ. The horizontal-pitZO is adapted to be closed by two hinged doors 23 which are suitably mounted on the sides of the horizontal pit Zilbyhinges '50 and meet inthe center of the pit. Any suitable bracing means may be provided-to support the doors 23 when they are in the closed position.

The side .pits are provided with longitudinal door 24 on the pit 2| and door 25 on the pit .22. The door24 is suitably hinged upon thesidepit 2| by hinges 2'6 and door 25 is. hinged by hinges 5|, and are thereby adapted to swing open away from the horizontal pits 2i and 22.

In theusual lift structure, the spaced longitudinalmembers -i2 are considerably less'than thewidth of an automobile frame, and therefore the length of the horizontal pit ZO and-the doors 23 is comparatively short. Therefore, the doors 23 are permitted to stand open incontact withthe hydraulic post i 0 when the lift i9; is: ex tended out of the pit 13. In the Figure 3..of the drawing, the lift I9 is shown extended from the pit it with the doors 23-leaning against the post It). In'other words, as the rear lift i9 is extended from the pit, the doors 2% are opened by the lift 19 pushing the doors, and they are merely pushed openfarenough to allow the cross member I! and the post it to "pass therethrough.- The doors 23 constantly lie inwardly against the post by gravitational force.

The doors24 and 25 on the side pits 2| and .22 are also adapted to be contacted-by the super- 4 structure, namely by the longitudinal members l2, and pushed out of the way to allow the longitudinal members I2 to pass thereby. After the members l2 have passed by the doors 24 and 25, however, the doors 24 and '25 will fall back shut because there is nothing to hold them open. Figure3 illustrates the closed position of the -doors24 and;;25; after the lift [9, has extended up outof' thepit l3, andthe leaning position of the doors 23.

The doors 23, 24 and 25, as described, are very easily .openedbythe superstructure of the lift [9 pushing up against the underside of the doors whentheglift; isextended out of the pit i3, but

.cthe'reverseprocedure, that is, opening the doors same manner because the doors must be subportedragainst downward movement to prevent an automobile or the weight of a person from openin -tee deo s i wr sdla. he. mpro d de 'rep n ne of his mv nt q "is plou ito op n t e doors: i adv: o the ar e s -r .e. o -tlie i t; k9. aady e i the ift 1H0 'nto-thepit 3.audtbemafierel sethe 1 01p. ,VeIbthQ; pit 13;.

lamae 1: oi: e-q .air-ides v th een ra layout ofthe trat d emb dim t of; the invena't-h st. asse .blv- 5.2 en iof thepit-iz andathrust ermaassflmbly-efi the et er end of..tbe.-pit.-2l. similarth u t e sua datatheex- :Each-th ustarm. asssm y is: n erconnectedbn means of a flexi e nka e means, 34 to :an. extension lever arm .:1-13;. the do rs fires illustrated. "Each ofzthe doors 24 and 25 are opened by the thrust arm. assemblies at;theirs.extrerxie-endsaridsthe thrust arm assembliesare:actuatedby: the. doors; 23..

The: operation .zofreach thrust arm assembly is substantiallyt the same, :and 1 therefore, in, order to: simplify the description of :this embodiment of #the invention, the description :to V follow "will be. limited. principally. to the structure and opera.- tion of thrust arm assembly 52;. on .door; 2 3.

"As :best illustrated in Figureffi, the". thrust ar-m assembly :52 includes an arm 21 :andtwo spaced universal jointsratconnected by an intermediate 'arm22. Arbell crank lever 28, best illustrated in-Figures. 2,:3 and-4, is providedto extend and retract-the arm;2l; and operate the door 24. 'The belllcrank lever :281is suitably pivoted on the side of the pit 13 by means :of :pivotplate29: and pivot pin :30. The arn'iiflis thereby adapted to be flexible to interconnect between the moving end of. the bell crank lever 28 and the swinging door 24, and yet remain sufliciently rigid to trans mit force between 'the bell crank lever and'the door.

In the Figures doors."23and extension leverarms. '33 are shown as 'beingswingable about the door hinges 53; The extension lever arms 33 extend in the iii-.- r ection opposite from the doors 23 down into the pit .13 as the doors '23 are swung open .out away from the pit I 3. The flexible linkage means, preferably a wire or chain 34, is used to-interconnect the bell .crankilever 23 and the extension lever arm 33, 'Thus, force may be transmitted from the extension lever. arm 33 by rotating. the doori23 about the xhinge' 5i! .therekOf, :butrotationof the bellzcr'ank leverzflil about the pivot Iii-r1130 will not transmit .force to the extensionglever arm 1.33. 'That'is, in the illusi'ireted embodiment :of the intention, the doors 2, 3 and 4 of the drawing, the

*5 23 are adapted to swing in'onlyone direction, namely, upwardly away from the pit I3, and therefore the extension lever arm 33 is adapted to swing in only one direction, and that is into the pit l3. Likewise, because the bell crank lever 28 is securely fastened to the arm 21, and the arm 21 is fastened to the door 24 and thereby" limited in its downward movement,the bell crank lever 23 is limited in its pivoting movement and cannot pull the chain 34 further than the position illustrated in Figure '2 of the drawing. On the other hand, the doors 24 and 25 may be opened while the doors 23 remain closed and will consequently move the arm 2'! and pivot the bell crank lever, but no force will be transmitted by the chain 34 to the extension lever arm 33.

In the operation of a lift having a pit covered by the improved doors of this invention, the superstructure including the cross member H and the spaced longitudinal members I2 on the post l may be started upwardly in the conventional manner. The superstructure, as'previously described, will contact the underside of the doors 23 and the doors 24 and 25, and thereby swing the doors open and push past the doors beyond the floor level above the pit [3. The doors 24 and 25 will fall shut upon the side pits 2| and 22 after the longitudinal members l2 have passed beyond contact with the doors 24 and 25. The doors 23, of course, will always lie in contact with the hydraulic post I ll and will thereby remain in the position substantially as illustrated in Figure 1 of the drawing while the hydraulic post ii! is extended out of the pit l3.

Cam members 35 are mounted near the top of the hydraulic post substantially in the position illustrated with relation to the longitudinally extending members I2. Therefore, as the superstructure is lowered toward the pit l3, the cam members 35 contact the doors 23 and move the doors 23 from the position illustrated in Figure 3 to the position illustrated in Figure 4. In the Figure 3, the chain 34 is illustrated extending between the bell crank lever 23 and the lever 33 with substantially no slack in the chain 34. This condition may be easily accomplished by adjusting the length of the chain 34. Because the chain is just long enough to extend between the bell crank lever 28 and the lever 33 when the doors 23 are in the position illustrated in Figure 3 against the side of the hydraulic post I 0, the doors 23 and 24 remain closed. That is, no driving force is transmitted from the levers 33 to the bell crank lever 28. However, the cam member 35 is adapted to contact the doors 23 and swing them further around the hinges 5B and open the doors 23 to a position substantially as illustrated in the Figure 4. Because the chain 34 is just sufficiently long to extend between the bell crank lever 28 and the end of the lever 33 when the doors 23 are against the hydraulic post In and the doors 24 and 25 are in the closed position as illustrated in Figure 3, it therefore follows that the chain 34 will be pulled by movement of the lever 33 from the position illustrated in Figure 3 to the further open position illustrated in Figure 4, and therefore the chain 34 will pivot the bell crank lever 28 about the pivot pin 35 and force the arm 21 upwardly to open the doors 24 and 25. The longitudinal members l2 may then pass downwardly through the opened pits 2| and 22 into the retracted position. As the post l0 and the cams 35 pass downwardly, the doors 23 swing shut and allow the chain 34 to slacken, and the doors 24 and 25 to close.

in the upward movement of the post H], the

cams35' will of course contact the doors 23 and swing them to, the maximum open position.

However, the longitudinal members l2 are positioned higher on the post l0 than the cams 35, and therefore the doors 24 and 25 will already be opened by the members l2. The lever arms 33 will swing when the cams 35 contact them and pull the chains 34, but the prior opening of the doors 24 and 25 by the members l2 will move the arms 2'! and bell crank 28, and the chain 34 will therefore be slack and the lever arms 33 will not affect the operation of the doors 24 and 25.

Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and-arrangement of parts may be resorted v to without departing from the spirit and the scope of the invention as hereinafter claimed.

What is claimed is: V

1. In a vehicle lift having a lift post with superstructure thereon, said post and superstructure being adapted to lower into a pit below a floor surface, the provision of closure doors adapted to automatically open and permit the superstructure to pass thereby and automatically reclose thereafter comprising, first door means closing a portion of said pit over the area of said post, second door means closing the remainder of the pit, first lever means operated by said first door means, second lever means adapted to pivot and operate said second door means, linkage means to link said first and second lever means, said linkage means having a predetermined degree of slack, and cam means on said lift to operate said first door means and first lever means, said slack in the the linkage to the second lever means adapting said second door means to remain closed until the said cam means operates said first door means to a predetermined position.

2. In a vehicle lift having a lift post with a substantially H-shaped superstructure thereon. a pit having a substantially H shape to receive said superstructure below fioor level, first door means hinged substantially at fioor level to close the pit over the area of said post, second door means hinged substantially at fioor level to cover the remainder of the pit, said first door means remaining open at all elevated positions of said lift in a leaning manner against said post, cam means carried by said lift to contact said first door means at one position of elevation of said lift and swing said first door means from said leaning position to an extended open position, and opening lever means for said second door means including linked drive means from said first door means operable to open said second door means by movement of said first door means from said leaning position to said extended open posiion.

3. In a vehicle lift having a lift post with a superstructure thereon, said post and superstructure being adapted to lower into a pit below a floor surface, the provision of closure doors adapted to automatically open and permit the superstructure to pass thereby and automatically reclose thereafter comprising, first hinged door means closing a portion of said pit over the area of said post, first lever means operated by said first door means, second hinged door means closing the remainder of said pit, second lever means smear? adapted to' pivot and open said second-door means, said first and second hinged door means being hinged a distance laterally of the superstructure and being openable by contact of the superstructure on the bottom thereof as the superstructure moves upwardly out of said pit, said post and superstructure having a vertical contour from the top thereof downwardly acting as a cam track against which said first door means rests, said first door means when resting against 2 said post being in a first open position, said contour including cam means protruding beyond said .post, said first door meanswhen resting against said cam means being in a second open position beyond said first position; flexible linkage means to link said first and :second lever means, said flexible linkage means having a predetermined length greater than the distance between said first lever means in said first position and any position ofsaid second lever means, said flexible a lever .meansiin said second openposition and the open position of said second lever: means, thereby operating said second lever means to open said second hinged door means and permit the superstructure to pass thereby, said first door means and first lever means being adapted to fall shut to a closed position by gravity after the superstructure has passed downwardly thereby, saidv flexible linkage having a length greater than the distance between said first lever means in said closed position and said second lever means.

THEODORE O. SNIDER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED .STATES PATENTS Number Name Date 530,776 :I-Iouser Dec. 11, 1894 548,606 Coe V- Oct. 22, 1895 2,262,121 .Snider Nov. 1'1, 1941 2,464,731 Thompson Mar. 15, 1949 

